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22-27 October 2018
Mahatma Mandir Conference Centre
Asia/Kolkata timezone
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Experimental Study of Multi-scale Interaction between (Intermediate, Small)-scale Microturbulence and MHD modes in EAST Plasmas

23 Oct 2018, 14:00
4h 45m
Mahatma Mandir Conference Centre

Mahatma Mandir Conference Centre

Gandhinagar (nearest Airport: Ahmedabad), India
Poster P2 Posters

Speaker

Dr Pengjun Sun (Institute of Plasma Physics, Chinese Academy of Sciences)

Description

Understanding plasma transport in phases with significant MHD activities (especially during plasma current ramp-up/down and disruption) in tokamak plasmas is crucial for predicting and thus controlling plasma behavior for future fusion devices, e.g. ITER. Since microturbulence plays an important role in driving anomalous plasma transport, the interactions between MHD modes and microturbulence is thought to be important in determining anomalous plasma transport [1]. Recent theoretical results in the literature show that microturbulence can nonlinearly interact with macro-instabilities such as kink/tearing mode through nonlinear cascade process or through temperature and/or density profile modulation from macro-instabilities. Due to the huge temporal and spatial scale separation between microturbulence and MHD modes, it is impossible for the present-day supercomputers to simulate their nonlinear interactions in a self-consistent way. In this talk, we present evidence of multi-scale interactions between (intermediate, small)-scale (kρ_i~2-6) microturbulence and MHD modes in EAST plasmas, including the first experimental identification of nonlinear coupling between microturbulence and an MHD mode during the current ramp-down phase in a set of L-mode plasmas in EAST [2] and the effects of 2/1 classical tearing mode on microturbulence [3] in the core of another set of EAST L mode plasmas using the EAST CO_2 laser collective scattering diagnostic in forward mode and far-forward mode. We demonstrate the nonlinear coupling between microturbulence and MHD mode with bispectral analysis [4] and envelope method [5], showing statistically significant bicoherence and modulated turbulent density fluctuation amplitudes correlated with the MHD mode. We also show that microturbulence spectral power is correlated to the 2/1 tearing mode and modulation effects on microturbulence by the 2/1 tearing mode. [1] P.J. Sun et al 2018 Nucl. Fusion 58 016003 [2] P.J. Sun et al 2018 Plasma Phys. Control. Fusion 60 025019 [3] Kim Y C and Powers E J 1979 IEEE Trans. Plasma Sci. PS-7 120 [4] Y. Nagashima et al 2005 Phys. Rev. Lett. 95095002 *Work supported by the National Natural Science Foundation of China with Contracts Nos.11475222, 11505228, 11735016, 11575238
Country or International Organization China, People's Republic of
Paper Number EX/P2-12

Primary author

Dr Pengjun Sun (Institute of Plasma Physics, Chinese Academy of Sciences)

Co-authors

Dr Bo Lv (Institute of Plasma Physics, Chinese Academy of Sciences) Dr Guojiang Wu (Institute of Plasma Physics, Chinese Academy of Sciences) Dr Hailin Zhao (Institute of Plasma Physics, Chinese Academy of Sciences) Dr Haiqing Liu (Institute of Plasma Physics, Chinese Academy of Sciences) Prof. Jiangang Li (Institute of Plasma Physics, Chinese Academy of Sciences) Dr Jizong Zhang (Institute of Plasma Physics, Chinese Academy of Sciences) Dr Liqing Xu (Institute of Plasma Physics, Chinese Academy of Sciences) Prof. Liqun Hu (Institute of Plasma Physics, Chinese Academy of Sciences) Dr Qun Li (Institute of Plasma Physics, Chinese Academy of Sciences) Dr Ran Chen (Institute of Plasma Physics, Chinese Academy of Sciences) Dr Tonghui Shi (Institute of Plasma Physics, Chinese Academy of Sciences) Prof. Xiaodong Zhang (Institute of Plasma Physics, Chinese Academy of Sciences) Prof. Yadong Li (Institute of Plasma Physics, Chinese Academy of Sciences) Dr Yang Ren (Princeton Plasma Physics Laboratory) Dr Yuming Wang (Institute of Plasma Physics, Chinese Academy of Sciences)

Presentation Materials

Paper